This invention relates to a magnetic head incorporated into a magnetic recording/reproducing apparatus, such as a VTR or a data storage device.
In the magnetic head, incorporated into the magnetic recording/reproducing apparatus, such as the VTR or the data storage device, a magnetic material formed of single-crystal ferrite is commonly employed as the material constituting a magnetic core.
The magnetic head is made up of magnetic core halves 81, 82, facing each other via a front gap g.sub.7 and a back gap g.sub.8 as a boundary and abutted and bonded to each other, as shown in FIG. 12. Each of the magnetic cores 81, 82 is formed of single-crystal ferrite. Track width suppression grooves 83, 84 are provided on the junction surfaces of the magnetic cores 81, 82 for restricting the track width of the magnetic gap g.sub.7.
Fused glass 87 is charged in the fused state in the track width suppressing grooves 83, 84 for bonding the magnetic cores 81, 82 together. Coil winding slots 89, 90 and winding guide slots 91, 92 are formed on the abutment surfaces and on the lateral surfaces of the magnetic cores 81, 82 so that coils, not shown, may be placed and wound via the coil winding slots 89, 90.
With the above-described magnetic heads, single-crystal ferrite is extensively used as the constituent material for the magnetic core. However, if the single-crystal ferrite is used, the ultimate magnetic head is changed significantly in abrasion resistance or electro-magnetic characteristics due to the difference in the orientation of the slicing surface.
Consequently, the selection of the crystal orientation is crucial when slicing a magnetic head from an ingot of the single-crystal ferrite. For example, with the use of the Mn--Zn single-crystal ferrite, there have hitherto been known a .beta. ferrite head having, for a surface facing the recording medium (medium facing surface), an abutting surface and a lateral surface, the planes {110}, {100} and {110}, and a J ferrite head having, for the medium facing surface, the abutting surface and the lateral surface, the {211}, {111} and {110} planes, respectively.
However, the .beta. and J ferrite heads have their own merits and demerits. That is, since the {211} plane is not satisfactory in abrasion resistance, as shown for example in FIG. 13, the magnetic head formed of J ferrite has a drawback that it is not satisfactory with respect to the abrasion resistance. On the other hand, with the magnetic heads which are extensively used in the VHS system, the electro-magnetic conversion characteristics of the magnetic head formed of J ferrite are a little better than those of the magnetic head formed of .beta. ferrite, such that it is extremely difficult to optimize the abrasion resistance and the electro-magnetic conversion characteristics simultaneously.
If the surface not satisfactory in abrasion resistance is used as the medium facing surface, as with the above-described J ferrite head, it may be contemplated to increase the depth length of the magnetic gap for assuring the service life of the magnetic head product. However, if the depth length is increased, the magnetic core efficiency of the magnetic head and also the electro-magnetic conversion characteristics are lowered.